function ex_PrincessMonster
bnd=newboundary([])
princess_pos=rand_pos_in_boundary(bnd);
monster_pos=rand_pos_in_boundary(bnd);

Princess=newplayer(...
'image','images/lady.jpg',...
'pos',princess_pos,...
'ang',0,...
'speed',1,...
'legend','b',...
'step_func',@s_random...
)

Monster=newplayer(...
'image','images/monster.jpg',...
'pos',monster_pos,...
'ang',0,...
'speed',0.6,...
'legend','r',...
'step_func',@s_random...
)


G=newgame({Princess,Monster},...
'axis',[-1,1,-1,1]*1.1,...
'h',0.1,...
'min_r',0.05,...
'pause','pause(G.h)',...
'boundary',bnd...
)

G=simgame(G)
